1. Technical Field
The present invention relates to improvements to multi-pass ovens and associated conveyor systems. More particularly, the invention relates to product centering and handling components which may be added to such systems to facilitate their operation. A product-centering apparatus ensures that products are maintained on conveyors within multi-pass ovens. Flanged slides help guide comestible products moving from one conveyor down to another conveyor as product pieces passes through a multi-pass oven.
2. Description of Related Art
Snack pieces and other edible baked goods are known to be prepared with the use of multi-pass ovens. While in these ovens, pieces are moved about on conveyors and pass from one conveyor to another in various ways. Conveyors are usually stacked one above another and rotate in a counter-current direction. Generally, relatively flat pieces remain stationary while being processed on such conveyors and while being handled and eventually packaged. No special handling is necessary to maintain the bulk of the product within the confines of process equipment. Such pieces remain on the equipment even when conveyors in an oven exhibit pronounced lateral movements due to irregular heating and other process imperfections.
However, certain product pieces are round or tubular and thus can move about during processing on conveyors, chutes and other equipment. These products have a stronger tendency to move around during processing as compared to relatively flat pieces. As conveyors continuously operate in a multi-pass arrangement, pieces reach the end of one conveyor and pass to an underlying subsequent conveyor by means of a chute or ramp. The chute imparts a forward motion to pieces which allows them to escape the process by rolling or bouncing off the sides or end of prior art conveyors.
In other circumstances, a piece may become entangled in stationary parts at the edge of a conveyor as a result of such movement. Propelled pieces may also end up sufficiently close to the edge of a conveyor so as to be lost from the sides of a chute as such pieces reach the end of a conveyor and are impelled against a chute. In these circumstances, there is an elevated risk of losing product, causing a defect in a product, or worse, stopping the system because of a malfunction when pieces are passed vertically from one conveyor to the next. Lost pieces may even serve as a fire hazard within an oven as pieces are exposed to sufficient heat to cause self-combustion.
FIG. 1 shows an embodiment of a prior art multi-pass oven. There are multiple conveyors 102, 122 turning counter-currently in an oven 120. In a multi-pass arrangement of conveyors 130, several conveyors 102 are stacked one above another. Each conveyor 102 turns around two or more axles 104. Each conveyor 102 generally turns in a different direction from the one above or below it. With multiple conveyors 102 within an oven 120, product pieces 106 are able to reside longer within the oven 120. Alternatively, a higher rate of production is possible in a multi-pass oven as conveyors can operate faster while maintaining a desired bake time. Operating conveyors at higher speeds impels pieces with a higher velocity thereby increasing the risk of losing processing pieces.
With reference to FIG. 1, once pieces 106 reach the end of a first conveyor 102, they fall 110 or are guided by chutes 124 to a product-receiving region 108 of a subsequent conveyor 122. Pieces passing to a subsequent conveyor 122 may end up traveling closer to the edge of a subsequent conveyor 122 and thus may be at a greater risk of eventually rolling or bouncing off of a subsequent conveyor 122. After passing to a subsequent conveyor 122, some pieces 112 may be immediately at risk for falling off of the conveyors.
A need exists for maintaining processing pieces 106 within the confines of conveyors within a multi-pass arrangement of conveyors. A need exists for guardrails or guide rails along the sides of a conveyor 102. Such side guards would maintain conveyed product pieces 106 on a conveyor. Such guide rails would ensure that product pieces 106 which are prone to movement during processing are maintained in the most central region of each conveyor. Further, a need exists for an improved chute. Such chutes would have guide rails which would help maintain product pieces within the confines of product chutes as product pieces 110 move from one conveyor to the next.
Such guide rails and improved chutes would substantially reduce the risk that conveyed pieces 106 are lost from, or cause a malfunction of, the conveyors during operation. Such guide rails and chutes would also reduce damage that can occur to product pieces 106. Such guide rails and chutes would not impede the movement of the conveyors and would be able to adjust as the conveyors exhibited random and lateral movements during operation. Such guide rails would not substantially impede monitoring of conveyed pieces and would be relatively inexpensive to produce and easy to install. Finally, such guide rails and chutes would substantially improve the safe operation of a multi-pass oven used to process product pieces which are prone to moving relative to a conveyor surface.